Feature: Add support for @DatabaseView annotations

This adds initial support for @DatabaseView annotations known from room. One test was added, further testing is needed. Implements pinchbv#130.

floor/pubspec.yaml

@@ -12,7 +12,8 @@ environment:
 dependencies:
   path: ^1.6.4
   sqflite: ^1.2.0
-  floor_annotation: ^0.6.0
+  floor_annotation:
+    path: ../floor_annotation
   meta: ^1.1.8
   flutter:
     sdk: flutter

floor_annotation/lib/floor_annotation.dart

@@ -3,6 +3,7 @@ library floor_annotation;
 export 'src/column_info.dart';
 export 'src/dao.dart';
 export 'src/database.dart';
+export 'src/database_view.dart';
 export 'src/delete.dart';
 export 'src/entity.dart';
 export 'src/foreign_key.dart';

floor_annotation/lib/src/database.dart

@@ -8,6 +8,10 @@ class Database {
   /// The entities the database manages.
   final List<Type> entities;
 
+  /// The views the database manages.
+  final List<Type> views;
+
   /// Marks a class as a FloorDatabase.
-  const Database({@required this.version, @required this.entities});
+  const Database(
+      {@required this.version, @required this.entities, this.views = const []});
 }

floor_annotation/lib/src/database_view.dart

@@ -0,0 +1,14 @@
+/// Marks a class as a database view (a fixed select statement).
+class DatabaseView {
+  /// The table name of the SQLite view.
+  final String viewName;
+
+  /// The SELECT query on which the view is based on.
+  final String query;
+
+  /// Marks a class as a database entity (table).
+  const DatabaseView(
+    this.query, {
+    this.viewName,
+  });
+}

floor_generator/lib/misc/constants.dart

@@ -5,6 +5,7 @@ abstract class AnnotationField {
 
   static const DATABASE_VERSION = 'version';
   static const DATABASE_ENTITIES = 'entities';
+  static const DATABASE_VIEWS = 'views';
 
   static const COLUMN_INFO_NAME = 'name';
   static const COLUMN_INFO_NULLABLE = 'nullable';
@@ -13,6 +14,9 @@ abstract class AnnotationField {
   static const ENTITY_FOREIGN_KEYS = 'foreignKeys';
   static const ENTITY_INDICES = 'indices';
   static const ENTITY_PRIMARY_KEYS = 'primaryKeys';
+
+  static const VIEW_NAME = 'viewName';
+  static const VIEW_QUERY = 'query';
 }
 
 abstract class ForeignKeyField {

floor_generator/lib/processor/dao_processor.dart

@@ -9,10 +9,12 @@ import 'package:floor_generator/processor/query_method_processor.dart';
 import 'package:floor_generator/processor/transaction_method_processor.dart';
 import 'package:floor_generator/processor/update_method_processor.dart';
 import 'package:floor_generator/value_object/dao.dart';
+import 'package:floor_generator/value_object/view.dart';
 import 'package:floor_generator/value_object/deletion_method.dart';
 import 'package:floor_generator/value_object/entity.dart';
 import 'package:floor_generator/value_object/insertion_method.dart';
 import 'package:floor_generator/value_object/query_method.dart';
+import 'package:floor_generator/value_object/queryable.dart';
 import 'package:floor_generator/value_object/transaction_method.dart';
 import 'package:floor_generator/value_object/update_method.dart';
 
@@ -21,20 +23,24 @@ class DaoProcessor extends Processor<Dao> {
   final String _daoGetterName;
   final String _databaseName;
   final List<Entity> _entities;
+  final List<View> _views;
 
   DaoProcessor(
     final ClassElement classElement,
     final String daoGetterName,
     final String databaseName,
     final List<Entity> entities,
+    final List<View> views,
   )   : assert(classElement != null),
         assert(daoGetterName != null),
         assert(databaseName != null),
         assert(entities != null),
+        assert(views != null),
         _classElement = classElement,
         _daoGetterName = daoGetterName,
         _databaseName = databaseName,
-        _entities = entities;
+        _entities = entities,
+        _views = views;
 
   @override
   Dao process() {
@@ -64,7 +70,8 @@ class DaoProcessor extends Processor<Dao> {
   List<QueryMethod> _getQueryMethods(final List<MethodElement> methods) {
     return methods
         .where((method) => method.hasAnnotation(annotations.Query))
-        .map((method) => QueryMethodProcessor(method, _entities).process())
+        .map((method) =>
+            QueryMethodProcessor(method, _entities, _views).process())
         .toList();
   }
 
@@ -114,10 +121,10 @@ class DaoProcessor extends Processor<Dao> {
         .toList();
   }
 
-  List<Entity> _getStreamEntities(final List<QueryMethod> queryMethods) {
+  List<Queryable> _getStreamEntities(final List<QueryMethod> queryMethods) {
     return queryMethods
         .where((method) => method.returnsStream)
-        .map((method) => method.entity)
+        .map((method) => method.queryable)
         .toList();
   }
 }

floor_generator/lib/processor/database_processor.dart

@@ -1,15 +1,17 @@
 import 'package:analyzer/dart/element/element.dart';
 import 'package:floor_annotation/floor_annotation.dart' as annotations
-    show Database, dao, Entity;
+    show Database, dao, Entity, DatabaseView;
 import 'package:floor_generator/misc/annotations.dart';
 import 'package:floor_generator/misc/constants.dart';
 import 'package:floor_generator/misc/type_utils.dart';
 import 'package:floor_generator/processor/dao_processor.dart';
 import 'package:floor_generator/processor/entity_processor.dart';
 import 'package:floor_generator/processor/error/database_processor_error.dart';
 import 'package:floor_generator/processor/processor.dart';
+import 'package:floor_generator/processor/view_processor.dart';
 import 'package:floor_generator/value_object/dao_getter.dart';
 import 'package:floor_generator/value_object/database.dart';
+import 'package:floor_generator/value_object/view.dart';
 import 'package:floor_generator/value_object/entity.dart';
 
 class DatabaseProcessor extends Processor<Database> {
@@ -27,10 +29,12 @@ class DatabaseProcessor extends Processor<Database> {
   Database process() {
     final databaseName = _classElement.displayName;
     final entities = _getEntities(_classElement);
-    final daoGetters = _getDaoGetters(databaseName, entities);
+    final views = _getViews(_classElement);
+    final daoGetters = _getDaoGetters(databaseName, entities, views);
     final version = _getDatabaseVersion();
 
-    return Database(_classElement, databaseName, entities, daoGetters, version);
+    return Database(
+        _classElement, databaseName, entities, views, daoGetters, version);
   }
 
   @nonNull
@@ -50,6 +54,7 @@ class DatabaseProcessor extends Processor<Database> {
   List<DaoGetter> _getDaoGetters(
     final String databaseName,
     final List<Entity> entities,
+    final List<View> views,
   ) {
     return _classElement.fields.where(_isDao).map((field) {
       final classElement = field.type.element as ClassElement;
@@ -60,6 +65,7 @@ class DatabaseProcessor extends Processor<Database> {
         name,
         databaseName,
         entities,
+        views,
       ).process();
 
       return DaoGetter(field, name, dao);
@@ -97,9 +103,30 @@ class DatabaseProcessor extends Processor<Database> {
     return entities;
   }
 
+  @nonNull
+  List<View> _getViews(final ClassElement databaseClassElement) {
+    final views = _classElement
+        .getAnnotation(annotations.Database)
+        .getField(AnnotationField.DATABASE_VIEWS)
+        ?.toListValue()
+        ?.map((object) => object.toTypeValue().element)
+        ?.whereType<ClassElement>()
+        ?.where(_isView)
+        ?.map((classElement) => ViewProcessor(classElement).process())
+        ?.toList();
+
+    return views;
+  }
+
   @nonNull
   bool _isEntity(final ClassElement classElement) {
     return classElement.hasAnnotation(annotations.Entity) &&
         !classElement.isAbstract;
   }
+
+  @nonNull
+  bool _isView(final ClassElement classElement) {
+    return classElement.hasAnnotation(annotations.DatabaseView) &&
+        !classElement.isAbstract;
+  }
 }

floor_generator/lib/processor/error/view_processor_error.dart

@@ -0,0 +1,19 @@
+import 'package:analyzer/dart/element/element.dart';
+import 'package:source_gen/source_gen.dart';
+
+class ViewProcessorError {
+  final ClassElement _classElement;
+
+  ViewProcessorError(final ClassElement classElement)
+      : assert(classElement != null),
+        _classElement = classElement;
+
+  InvalidGenerationSourceError get MISSING_QUERY {
+    return InvalidGenerationSourceError(
+      'There is no SELECT Query defined on the entity ${_classElement.displayName}.',
+      todo:
+          'Define a SELECT query for this View with @DatabaseView(\'SELECT [...]\') ',
+      element: _classElement,
+    );
+  }
+}

floor_generator/lib/processor/query_method_processor.dart

@@ -7,22 +7,28 @@ import 'package:floor_generator/misc/constants.dart';
 import 'package:floor_generator/misc/type_utils.dart';
 import 'package:floor_generator/processor/error/query_method_processor_error.dart';
 import 'package:floor_generator/processor/processor.dart';
+import 'package:floor_generator/value_object/view.dart';
 import 'package:floor_generator/value_object/entity.dart';
 import 'package:floor_generator/value_object/query_method.dart';
+import 'package:floor_generator/value_object/queryable.dart';
 
 class QueryMethodProcessor extends Processor<QueryMethod> {
   final QueryMethodProcessorError _processorError;
 
   final MethodElement _methodElement;
   final List<Entity> _entities;
+  final List<View> _views;
 
   QueryMethodProcessor(
     final MethodElement methodElement,
     final List<Entity> entities,
+    final List<View> views,
   )   : assert(methodElement != null),
         assert(entities != null),
+        assert(views != null),
         _methodElement = methodElement,
         _entities = entities,
+        _views = views,
         _processorError = QueryMethodProcessorError(methodElement);
 
   @nonNull
@@ -42,11 +48,16 @@ class QueryMethodProcessor extends Processor<QueryMethod> {
       returnsStream,
     );
 
-    final entity = _entities.firstWhere(
-        (entity) =>
-            entity.classElement.displayName ==
-            flattenedReturnType.getDisplayString(),
-        orElse: () => null); // doesn't return an entity
+    final Queryable queryable = _entities.firstWhere(
+            (entity) =>
+                entity.classElement.displayName ==
+                flattenedReturnType.getDisplayString(),
+            orElse: () => null) ??
+        _views.firstWhere(
+            (view) =>
+                view.classElement.displayName ==
+                flattenedReturnType.getDisplayString(),
+            orElse: () => null);
 
     return QueryMethod(
       _methodElement,
@@ -55,7 +66,7 @@ class QueryMethodProcessor extends Processor<QueryMethod> {
       rawReturnType,
       flattenedReturnType,
       parameters,
-      entity,
+      queryable,
     );
   }